基于改进SVPWM策略的双直流端口整流器功率分配方法

研究了一种三相三端口AC-DC变换器的空间矢量脉宽调制(SVPWM)策略及功率分配方法，可用作独立新能源供电系统中的接口变换器。该变换器通过蓄电池与新能源装置的协调配合，可以平衡新能源装置固有的功率波动。变换器拓扑形式与传统T形三电平AC-DC变换器类似，分离出直流侧的一个分压电容作为蓄电池端口，交流侧与直流输出、蓄电池端口之间均为单级功率变换。沿用传统SVPWM策略，分析得到不对称三电平工况下的改进型SVPWM策略。通过分析开关矢量对应的功率流向，说明调节矢量作用时间可以实现2个直流端口的功率分配，并得到功率分配的闭环控制方式。对变换器的功率调节范围、电感电流纹波、功率密度等特性进行了详细分析。仿真结果验证了理论分析的正确性和变换器在效率方面的优势。

Power Distribution Method of Rectifier with Two DC Ports Based on Modified SVPWM Strategy

A space vector pulse width modulation(SVPWM)strategy and power distribution method of a three-phase three-port AC-DC converter are investigated, which can serve as an interface converter for stand-alone renewable power supply systems. The inherit power fluctuation from the new energy devices can be minimized by cooperation of the batteries and new energy devices. The topology of the converter is similar to that of a traditional T-type three-level AC-DC converter, with a partial-voltage capacitor on the DC side acting as the battery port. Single stage power conversion is established between the AC port and the DC output port, as well as between the AC port and the battery port. A modified SVPWM strategy for asymmetric three-level operating condition is obtained based on the traditional SVPWM strategy. By analyzing the power flow directions corresponding to different switching vectors, it is verified that power distribution between the two DC ports can be reached by adjusting working time of switching vectors. A closed-loop power distribution method is thereby established. The power range, current ripple and power density of the converter are discussed in detail. The simulation results support the theoretical conclusions and prove the high efficiency of the converter.